With iOS 8, Apple introduced extensibility in the OS through apps with built-in extensions that can be used inside of other apps like Safari, Photos, the Notification Center, and more. Several app updates have been released that focus on further integrating iOS with extensions. Here are just three must-have apps with extension support in iOS 8.

1Password is the venerable password utility that feels at home on the Mac, but it can now feel just as comfortable on iOS. This is because 1Password now includes a Safari extension that lets you easily access your passwords without ever leaving the website that needs you to authenticate with your 1Password-stored credentials. After selecting your password through the Safari extension, 1Password will autofill in your credentials without you having to lift a finger.

To enable the 1Password extension, do this:

Open the 1Password application and synchronize your 1Password database, or add some accounts to the application that can be used to autofill your usernames and passwords online.

After the application has been launched, you can add the extension by navigating to Safari | Share button | More button on second row (the Actions row)

Flip the switch for 1Password to ON (Figure A)

Figure A

You must enable extensions in the "More..." Action panel in Safari.

You'll only need to perform these steps once per device in order to activate the 1Password extension in Safari. Once activated, you can begin using the extension to sign into websites.

To use the 1Password extension to sign into websites in Safari, do the following:

Navigate to a website login form

Select the Share button | 1Password (Figure B)

Enter your 1Password master password to unlock the application

Select the login that you wish to use for that site

Figure B

After activating the extension, it'll be available in the Actions section of the share sheet in Safari.

Once you've selected the account in the 1Password extension, your credentials for the site will be autofilled for you. Simply tap the submit button for the login form on the site.

Why it's a must-have: From Touch ID support to the new Safari extension, 1Password has truly taken iOS 8 extensions to the max. The best part is that they've made 1Password completely free, and it's only $9.99 if you want to get the Pro features.

PCalc has been around on the Mac for more than 22 years, and its iOS counterpart has been around for a number of years as well. PCalc takes the basics of the iOS calculator and puts the features on steroids, making it one of the most powerful calculators available on iOS and the Mac. While it won't replace your TI-83, it has some great features for everyday calculations, including unit conversions.

Before we begin using the PCalc extension, we first need to activate it in the Notification Center by performing the following steps (you'll only need to do this once per device):

Open the Notification Center by swiping down from the top of the screen

Scroll down to the bottom of the Notification Center list, and tap the Edit button

Tap the plus sign [+] next to PCalc to have it added to the Today view (Figure C)

Figure C

Extensions can also be activated and shown in the Today view in the iOS Notification Center.

Once the extension has been enabled, you'll now have a calculator in the Today view of the Notification Center that can be accessed in any application — even through the lock screen by swiping down from the top of the screen to reveal the Notification Center (Figure D).

Figure D

The PCalc widget is capable of doing basic math, and it's very easily accessible in the Notification Center from the lock screen or any application.

Why it's a must-have: The lite and paid versions of PCalc include the Notification Center-based calculator for even easier basic math. If you need quick access for adding, subtracting, multiplying, and dividing, then PCalc is a tool that you simply cannot pass up.

The Omni Group's OmniFocus has long been a go-to solution for managing time, keeping track of tasks, and organizing tasks into groups based on context. It's the ultimate task management system. In iOS 8, this tool gets even better by enabling a Today widget that can provide easy access to important and upcoming to-do items, without having to enter the application.

To enable this extension, perform the same steps above for enabling PCalc, except select the plus sign [+] next to OmniFocus. This will place the OmniFocus widget in the Today view of the Notification Center.

Once you've enabled the widget, you can begin using it by opening the Notification Center. Simply swipe down from the top of the screen while in any application, the home screen, or the lock screen in iOS (Figure E).

Figure E

The OmniFocus Today widget presents a list of upcoming to-do items that need to be completed, and it offers a UI to complete those items without returning to the OmniFocus app.

When looking at to-do items in this view, you can tap the to-do to open it in OmniFocus, or you can tap the completion button to the right of the to-do to mark it off. Once you've marked an item as completed, it'll sync back to OmniFocus on your Mac and other iOS devices (if you have sync enabled).

Why it's a must-have: OmniFocus has been a go-to to-do list management and tracking system for years, and it continually gets better with age. With the iOS 8 version of the app, you can now view your upcoming to-do items right from the Today view in the Notification Center of iOS, or from the lock screen, without ever needing to fully wake your device and launch the app.

Where to find more apps like these

Apple has recently been pushing applications with extensions into the App Store, and they've created an Extend Your Apps category in the store where all apps that have extensions can be found.

Have you found an application extension that you can't live without in iOS 8? Let us know in the discussion thread below.

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About Cory Bohon

Cory Bohon is an indie developer specializing in iOS and OS X development. He runs a software company called Cocoa App and is also a developer at MartianCraft. He was introduced to technology at an early age and has been writing about his favorite te...

Disclosure

Cory Bohon is an indie developer, creating both iOS and OS X applications at Cocoa App (his own company), MartianCraft, and for various other clients. As a part of full disclosure, he does not write about any software that he has created or has helped to create through these outlets.

Full Bio

Cory Bohon is an indie developer specializing in iOS and OS X development. He runs a software company called Cocoa App and is also a developer at MartianCraft. He was introduced to technology at an early age and has been writing about his favorite technology part-time since 2007. He runs a development blog named ObjDev when he isn’t writing about consumer tech.